Air-break electric switch



Oct. 8, 1929. G. w. OKEEFFE AIR BREAK ELECTRIC SWITCH Filed May 19, 1928 Patented Oct. 8, 1929 UNITED STATES GEORGE W. OKEEFFE, OF MILTON,

PATENT; OFFICE MASSACHUSETTS, ASSIGNOR TO GONDIT ELECTRI- GAL MANUFACTURING CORPORATION, OF SOUTH BOSTON, MASSACHUSETTS, A OOB- PORATION OF MASSACHUSETTS AIR-BREAK ELECTRIC SWITCH Application filed May 19,.

This invention relates to air break electric switches especially for motor starting service.

In such a switch the sets of separable contact members that are associated with the various phases of the circuit are isolated from is one of the essential elements of the switch and it is not intended that the switch should be operated without the arc chute. The are chutes, or contact housings, are usually removable so that access to the contact members can be gained readily for the purpose of inspecting, cleaning and adjusting the contact members. It frequently happens that a workman fails to replace the arc chute in position after he has overhauled, the switch. Consequently, the circuit interrupting arcs are free to commingle when the switch is opened under heavy load. Serious damage can thus occur.

It is an objectof the present invention to provide an electric switch of the type above set forth with improved means to prevent the operation of the switch when the are chute is not inproper position.

A further object of the invention is the provision of means to interpose automatically an obstacle in the path of movement of the movable switch members that will prevent their moving into engagement with the cooperating movable contact members when the arc chute or housing is not in place. 1

A' further object is generally to improve the construction and operation of electric switches.

Fig. 1 is a front elevation of an electric switch embodying the present invention with the cover of the enclosing casing removed.-

Fig. 2 is a section taken along line 22 of Fig. 1.

Fig. 3 is a perspective view of the remov able arc chute which encloses the sets of 00- operating contact members.

Fig. 4 is a view similar to Fig. 2 with the arc chute and cover removed.

The electric switch embodying thepresent invention includes an enclosing casing formed 1928. Serial No. 279,139.

of two complementary parts. The part 10 comprises a support for the switch and the part 12 isremovable and comprises a cover for the casing. The switch is supported on a plate 13 located within the casing and secured r56 to the part 10 thereof.

The switch here shown is of the three phase type and is provided with three sets of stationary contact members 14 which are secured 1n spaced'hor'izontal alignment to the upper portion of the supporting plate 13. Cooperating movable contact members 16 are supported on spring urged carrier 18 that are pivotally supported on an insulating bar 20. Saidbar is secured to the arms of a bi-furcatediba'r 22 that is attached to the armature 24 of a switch operating-electro-magnet 26 carried by the supporting plate 13 at the lower portion thereof. Said armature2 i is pivoted in front of the pole faces of the electro-magnet on a pivot pin 27. The electro-magnet is provided with an actuating coil 28 that is adapted to be maintained energized to hold the switch closed. The movable contact members and associated operating mechanism are adapted to move by gravity in a counterclockwise direction into a switch open position.

The sets of cooperating contact members are enclosed in an arc chute or housing 30 which is formed. of insulating material and has a plurality of contact compartments 32, see especially Fig. 8, in each of which a separate set of contact members are located. The are chute is located removably in the position illustrated in Fig. 2 and has a vertical slots 3 1 in its end walls in which upstanding projections 36 carried by and extending inwardly from the casing are loosely received. Said projections serve to support the arc chute removably in position and the arc chute can be removed from the aforesaid relation and from the casing by detaching it from said projections 36.

In accordance with this invention, means controlled by the arc chute are providedto interpo'se automatically a barrier or obstacle in the path of movement of the movable switch member whereby to prevent complete closing of the switch when the barrier is not in place. As here shown, the barriercom:

prises an insulating body 38 which is secured member when said are chute is removed,

40 that is guided for vertical movements in a bracket 42 carried by a top wall of the enclosing casing. The barrier 38 is located above and in front of the stationary contact member 14 of the middle set of contact members and is normally held in elevated position by and wherein it is in front ofthe stationarycontact member 14 and is located in the path of move,v

ment of the movable switch member. The switch thus can not be completely closed, and damage due to the absence of the arc chute is prevented.

My concurrently filed application Serial No. 279,138, shows and claims broadly means controlled by the removable arc chute for preventing the closing of the switch.

I claim:

1. An electric switch having stationary and movable contact members, an arc chute removably located in cooperative position 3 with said contact members, and means controlled by said chute to obstruct the closing movement of said movable contact member,

2. An electric switch having stationary and movable contact members, an arc chute removably located in cooperative position with said contact member, and a barrier Ladapted to move in between the separated contact members when said are chute is removed from the aforesaid position. 3. An electric switch having stationary and movable contact members, an arc chute removably located in cooperative position with said contact members, and a barrier adapted to move in between the separated contact members when said are chute is removed from the aforesaid position, said chutebeing normally located between said barrier and contact members. 4

4. An electric switch having stationary and movable contact members, an arc chute removably located in cooperative position with said .contact members, an insulating barrier movably/supported above and in engagement with said removable arc chute and above and in front of said stationary contact member and being free to fall into the path of closing movement of said movable contact member when said are chute is removed from its aforesaid position.

5. An electric switch having stationary and movable contact members, an arc chute removably located in cooperative position with respect to said contact members and having a top Wall, a support located above said contact members, a barrier movable in said support and pormally engagin the top wall of said arc chute, said barrier eing freeto descend into position in front of saidmovable switch Y name to this specification.

to the lower end of a vertically extended rod whereby to prevent the closing of the switch.

In testimony whereof, I have signed my GEORGE w. OKEEFFE. 7o 

